Phylogenetic revision of the North American Asidini (Coleoptera: Tenebrionidae)

The asidine darkling beetles (Coleoptera: Tenebrionidae: Asidini) are a morphologically diverse tribe of flightless tenebrionids found in many arid and sub‐arid habitats around the world. The 260 currently described North American species are contained in 27 genera, all of which are restricted to the western half of the continent. Evolutionary relationships within and between the North American Asidini (Coleoptera: Tenebrionidae) genera were reconstructed using partial sequences of mitochondrial cytochrome c oxidase I (COI) (660 bp) and nuclear ribosomal 28S (D2 region) (492 bp), and 100 phenotypic characters for 50 North American asidine species, representing 20 of the 27 currently described genera and 1 new genus. Species from two additional tenebrionid tribes (Branchini and Coniontini) and the South American asidine genus Cardigenius were chosen as outgroups. Analyses were performed using maximum parsimony and Bayesian inference methods. Clade support was inferred based on the posterior probability distribution of tree topologies, nonparametric bootstrap analysis, and partitioned Bremer support indices. The generic classification of the North American Asidini is revised based on the results, with ten genera recognized. Seven current genera: Craniotus LeConte, Heterasida Casey, Litasida Casey, Microschatia Solier, Pelecyphorus Solier, Philolithus Lacordaire, Stenomorpha Solier, are redescribed, and Ardamimicus Smith gen.n ., Ferveoventer Smith gen.n . and Micrasida Smith gen.n . are described, including Ardamimicus cognatoi Smith sp.n ., Ferveoventer browni Smith sp.n . and Micrasida obrienorum Smith sp.n . Twenty current genera are treated as subgenera pending further analyses: Philolithus Lacordaire with subgenera Glyptasida Casey, Gonasida Casey, Herthasida Wilke and Tisamenes Champion; Pelecyphorus Solier, with subgenera: Astrotus LeConte, Parasida Casey (= Plesiasida nom.n ), Poliorcetes Champion, Sicharbas Champion, Stenosides Solier, Ucalegon Champion and Zaleucus Champion, and Stenomorpha Solier with subgenera Asidina Casey, Asidopsis Casey, Bothrasida Casey, Megasida Casey, Notiasida Casey, Platasida Casey, Pycnomorpha Motschulsky, Stethasida Casey and Trichiasida Casey; all stat.rev .     

Evidence for frequency‐dependent selection maintaining polymorphism in the Batesian mimic Papilio polytes in multiple islands in the Ryukyus,Japan

Batesian mimicry is a well‐studied adaptation for predation avoidance, in which a mimetic species resembles an unpalatable model species. Batesian mimicry can be under positive selection because of the protection gained against predators, due to resemblance to unpalatable model species. However, in some mimetic species, nonmimetic individuals are present in populations, despite the benefits of mimicry. The mechanism for evolution of such mimetic polymorphism remains an open question. Here, we address the hypothesis that the abundance of mimics is limited by that of the models, leading to mimetic polymorphism. In addition, other forces such as the effects of common ancestry and/or isolation by distance may explain this phenomenon. To investigate this question, we focused on the butterfly, Papilio polytes, that exhibits mimetic polymorphism on multiple islands of the Ryukyus, Japan, and performed field surveys and genetic analysis. We found that the mimic ratio of P. polytes was strongly correlated with the model abundance observed on each of the five islands, suggesting negative frequency‐dependent selection is driving the evolution of polymorphism in P. polytes populations. Molecular phylogenetic analysis indicated that the southern island populations are the major source of genetic diversity, and the middle and northern island populations arose by relatively recent migration. This view was also supported by mismatch distribution and Tajima's D analyses, suggesting a recent population expansion on the middle and northern islands, and stable population persistence on the southern islands. The frequency of the mimetic forms within P. polytes populations is thus explained by variations in the model abundance rather than by population structure. Thus, we propose that predation pressure, rather than neutral forces, have shaped the Batesian mimicry polymorphism in P. polytes observed in the Ryukyus.     

Testing the adaptive hypothesis of Batesian mimicry among hybridizing North American admiral butterflies

Batesian mimicry is characterized by phenotypic convergence between an unpalatable model and a palatable mimic. However, because convergent evolution may arise via alternative evolutionary mechanisms, putative examples of Batesian mimicry must be rigorously tested. Here, we used artificial butterfly facsimiles (N = 4000) to test the prediction that (1) palatable Limenitis lorquini butterflies should experience reduced predation when in sympatry with their putative model, Adelpha californica, (2) protection from predation on L. lorquini should erode outside of the geographical range of the model, and (3) mimetic color pattern traits are more variable in allopatry, consistent with relaxed selection for mimicry. We find support for these predictions, implying that this convergence is the result of selection for Batesian mimicry. Additionally, we conducted mark–recapture studies to examine the effect of mimicry and found that mimics survive significantly longer at sites where the model is abundant. Finally, in contrast to theoretical predictions, we found evidence that the Batesian model (A. californica) is protected from predation outside of its geographic range. We discuss these results considering the ongoing hybridization between L. lorquini and its sister species, L. weidemeyerii, and growing evidence that selection for mimicry predictably leads to a reduction in gene flow between nascent species.     

Is inaccurate mimicry ancestral to accurate in myrmecomorphic spiders (Araneae)?

Batesian mimicry, in which a palatable organism resembles an unpalatable model, is widespread among taxa. Batesian mimics can be classified based on their level of accuracy (inaccurate or accurate). Using data on defensive strategies in more than 1000 species of spiders I investigated whether inaccurate myrmecomorphy is ancestral to accurate myrmecomorphy. I classified 233 myrmecomorphic species into four accuracy levels based on morphology, from poor inaccurate mimics to very accurate ones. I found that myrmecomorphy has evolved independently in 16 families and 85 genera. On the family‐level phylogeny, the occurrence of myrmecomorphy is confined mainly to families branching later on the tree, from the RTA clade. On the generic‐level phylogenies in Corinnidae and Salticidae, myrmecomorphy is not only of derived origin. Estimated ancestral state was non‐mimetic in Salticidae and poor inaccurate myrmecomorphy in Corinnidae. Thus, inaccurate myrmecomorphic spider mimics seem rather ancestral to accurate but additional analysis on species‐level phylogenies is needed to support this conclusion. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 97–111.     

Multi-gene phylogeny of North American clear-winged moths (Lepidoptera: Sesiidae): a foundation for future evolutionary study of a speciose mimicry complex

Sesiids are a diverse group of predominantly diurnal moths, many of which are Batesian mimics of Hymenoptera. However, their diversity and relationships are poorly understood. A multi-gene phylogenetic analysis of 48 North American sesiid species confirmed the traditional taxonomic tribal ranks, demonstrated the paraphyly of Carmenta and Synanthedon with respect to several other genera and ultimately provided minimal phylogenetic resolution within and between North American and European groups. Character support from each gene suggested inconsistency between the phylogenetic signal of the CAD gene and that of the other four genes. However, removal of CAD from subsequent phylogenetic analyses did not substantially change the initial phylogenetic results or return Carmenta and Synanthedon as reciprocally monophyletic, suggesting that it was not impacting the overall phylogenetic signal. The lack of resolution using genes that are typically informative at the species level for other lepidopterans suggests a surprisingly rapid radiation of species in Carmenta/Synanthedon. This group also exhibits a wide range of mimicry strategies and hostplant usage, which could be fertile ground for future study.     

Diversity of warning signal and social interaction influences the evolution of imperfect mimicry

Mimicry, the resemblance of one species by another, is a complex phenomenon where the mimic (Batesian mimicry) or the model and the mimic (Mullerian mimicry) gain an advantage from this phenotypic convergence. Despite the expectation that mimics should closely resemble their models, many mimetic species appear to be poor mimics. This is particularly apparent in some systems in which there are multiple available models. However, the influence of model pattern diversity on the evolution of mimetic systems remains poorly understood. We tested whether the number of model patterns a predator learns to associate with a negative consequence affects their willingness to try imperfect, novel patterns. We exposed week‐old chickens to coral snake (Micrurus) color patterns representative of three South American areas that differ in model pattern richness, and then tested their response to the putative imperfect mimetic pattern of a widespread species of harmless colubrid snake (Oxyrhopus rhombifer) in different social contexts. Our results indicate that chicks have a great hesitation to attack when individually exposed to high model pattern diversity and a greater hesitation to attack when exposed as a group to low model pattern diversity. Individuals with a fast growth trajectory (measured by morphological traits) were also less reluctant to attack. We suggest that the evolution of new patterns could be favored by social learning in areas of low pattern diversity, while individual learning can reduce predation pressure on recently evolved mimics in areas of high model diversity. Our results could aid the development of ecological predictions about the evolution of imperfect mimicry and mimicry in general.     

Why are there so many mimicry rings? Correlations between habitat,behaviour and mimicry in Heliconius butterflies

In the new world tropics there is an extravagant array of sympatric butterfly mimicry rings. This is puzzling under strictly coevolutionary (Müllerian) mimicry: all unpalatable species should converge as ‘co-mimics' to the same pattern. If mimicry has usually evolved in unpalatable species by one-sided (Batesian) evolution, however, it is easy to see that mimicry rings centred on different models could remain distinct. If mimicry rings were also segregated by habitat, a diversity of mimicry rings could be stabilized. In this paper we report correlations between behaviour and mimicry of nine unpalatable Heliconius species. It is already known that co-mimics fly in similar habitats, and non-mimics fly in different habitats, although there is much overlap. Contrary to a previous report, we find little difference in flight heights of heliconiine mimicry rings; all species fly from ground level to the canopy. However, co-mimics roost at night in similar habitats and at similar heights above the ground, but in different habitats and at different heights from species in other mimicry rings. Heliconius (especially the erato taxonomic group) are renowned for roosting gregariously; and co-mimics roost gregariously with each other more often than with non-mimics. Gregarious roosting is therefore common between species, as well as within species. There are thus strong links between mimicry and behavioural ecology in Heliconius. The paradoxical correlation between nocturnal roosting and visual mimicry is presumably explained by bird predation at dusk when roosts are forming, or at dawn before they have disbanded. Direct evidence of predation is lacking, but there are high rates of disturbance by birds at these times. These results, together with knowledge of the phylogeny of Heliconius, suggest that species from the melpomene-group of Heliconius have radiated to occupy mimetic niches protected by model species in the Ithomiinae and the erato-group of Heliconius. A variety of sympatric mimicry rings is apparently maintained because key models fail to converge, while more rapidly-evolving unpalatable mimics evolve towards the colour patterns of the models. The maintenance of mimetic diversity would be aided by the habitat and behavioural differences between mimicry rings revealed here, provided that different predators are found in different habitats. This explanation for the maintenance of multiple mimicry rings is more plausible for Heliconius mimicry than alternatives based on visual mating constraints, thermal ecology, or camouflage.     

High-model abundance may permit the gradual evolution of Batesian mimicry: an experimental test

In Batesian mimicry, a harmless species (the ‘mimic’) resembles a dangerous species (the ‘model’) and is thus protected from predators. It is often assumed that the mimetic phenotype evolves from a cryptic phenotype, but it is unclear how a population can transition through intermediate phenotypes; such intermediates may receive neither the benefits of crypsis nor mimicry. Here, we ask if selection against intermediates weakens with increasing model abundance. We also ask if mimicry has evolved from cryptic phenotypes in a mimetic clade. We first present an ancestral character-state reconstruction showing that mimicry of a coral snake (Micrurus fulvius) by the scarlet kingsnake (Lampropeltis elapsoides) evolved from a cryptic phenotype. We then evaluate predation rates on intermediate phenotypes relative to cryptic and mimetic phenotypes under conditions of both high- and low-model abundances. Our results indicate that where coral snakes are rare, intermediate phenotypes are attacked more often than cryptic and mimetic phenotypes, indicating the presence of an adaptive valley. However, where coral snakes are abundant, intermediate phenotypes are not attacked more frequently, resulting in an adaptive landscape without a valley. Thus, high-model abundance may facilitate the evolution of Batesian mimicry.     

A central role for p38 MAPK in the early transcriptional response to stress

A study using phylogenetic hypothesis testing, published in BMC Evolutionary Biology, suggests that non-mimetic forms of the North American white admiral butterfly evolved from a mimetic ancestor. This case might provide one of the first examples in which mimicry was gained and then lost again, emphasizing the evolutionary lability of Batesian mimicry. See research article http://www.biomedcentral.com/1471-2148/10/239     

Population genetic structure and evolution of Batesian mimicry in Papilio polytes from the Ryukyu Islands,Japan, analyzed by genotyping‐by‐sequencing

Batesian mimicry is a striking example of Darwinian evolution, in which a mimetic species resembles toxic or unpalatable model species, thereby receiving protection from predators. In some species exhibiting Batesian mimicry, nonmimetic individuals coexist as polymorphism in the same population despite the benefits of mimicry. In a previous study, we proposed that the abundance of mimics is limited by that of the models, leading to polymorphic Batesian mimicry in the swallowtail butterfly, Papilio polytes, on the Ryukyu Islands in Japan. We found that their mimic ratios (MRs), which varied among the Islands, were explained by the model abundance of each habitat, rather than isolation by distance or phylogenetic constraint based on the mitochondrial DNA (mtDNA) analysis. In the present study, this possibility was reexamined based on hundreds of nuclear single nucleotide polymorphisms (SNPs) of 93 P. polytes individuals from five Islands of the Ryukyus. We found that the population genetic and phylogenetic structures of P. polytes largely corresponded to the geographic arrangement of the habitat Islands, and the genetic distances among island populations show significant correlation with the geographic distances, which was not evident by the mtDNA‐based analysis. A partial Mantel test controlling for the present SNP‐based genetic distances revealed that the MRs of P. polytes were strongly correlated with the model abundance of each island, implying that negative frequency‐dependent selection interacting with model species shaped and maintained the mimetic polymorphism. Taken together, our results support the possibility that predation pressure, not isolation by distance or other neutral factors, is a major driving force of evolution of the Batesian mimicry in P. polytes from the Ryukyus.     

Once a Batesian mimic, not always a Batesian mimic: mimic reverts back to ancestral phenotype when the model is absent

Batesian mimics gain protection from predation through the evolution of physical similarities to a model species that possesses anti-predator defences. This protection should not be effective in the absence of the model since the predator does not identify the mimic as potentially dangerous and both the model and the mimic are highly conspicuous. Thus, Batesian mimics should probably encounter strong predation pressure outside the geographical range of the model species. There are several documented examples of Batesian mimics occurring in locations without their models, but the evolutionary responses remain largely unidentified. A mimetic species has four alternative evolutionary responses to the loss of model presence. If predation is weak, it could maintain its mimetic signal. If predation is intense, it is widely presumed the mimic will go extinct. However, the mimic could also evolve a new colour pattern to mimic another model species or it could revert back to its ancestral, less conspicuous phenotype. We used molecular phylogenetic approaches to reconstruct and test the evolution of mimicry in the North American admiral butterflies (Limenitis: Nymphalidae). We confirmed that the more cryptic white-banded form is the ancestral phenotype of North American admiral butterflies. However, one species, Limenitis arthemis, evolved the black pipevine swallowtail mimetic form but later reverted to the white-banded more cryptic ancestral form. This character reversion is strongly correlated with the geographical absence of the model species and its host plant, but not the host plant distribution of L. arthemis. Our results support the prediction that a Batesian mimic does not persist in locations without its model, but it does not go extinct either. The mimic can revert back to its ancestral, less conspicuous form and persist.     

Body size as a primary determinant of ecomorphological diversification and the evolution of mimicry in the lampropeltinine snakes (Serpentes: Colubridae)

Evolutionary correlations between functionally related character suites are expected as a consequence of coadaptation due to physiological relationships between traits. However, significant correlations may also exist between putatively unrelated characters due to shared relationships between those traits and underlying variables, such as body size. Although such patterns are often dismissed as simple body size scaling, this presumption may overlook important evolutionary patterns of diversification. If body size is the primary determinant of potential diversity in multiple unrelated characters, the observed differentiation of species may be governed by variability in body size, and any biotic or abiotic constraints on the diversification thereof. Here, we demonstrate that traits related to both predatory specialization (gape and diet preference) and predatory avoidance (the development of Batesian mimicry) are phylogenetically correlated in the North American snake tribe Lampropeltini. This is apparently due to shared relationships between those traits and adult body size, suggesting that size is the primary determinant of ecomorphological differentiation in the lampropeltinines. Diversification in body size is apparently not linked to climatic or environmental factors, and may have been driven by interspecific interactions such as competition. Additionally, we find the presence of a ‘key zone’ for the development of both rattle‐ and coral snake mimicry; only small snakes feeding primarily on ectothermic prey develop mimetic colour patterns, in or near the range of venomous model species.     

Aide memoire mimicry*

Abstract. 1. Animals and plants may gain protection by reminding would-be aggressors of failure, or an unpleasant experience following an attempt at capture and ingestion. Thus they need not be mistaken for noxious or dangerous prey; defence is adequate if the aggressor is forced to recall the attributes of such species, or the disagreeable sequela to a previous assault upon them. 2. Batesian mimics and mildly toxic Mullerian mimics can also add to their repertoire by such defensive strategies. 3. Several examples of this phenomenon, designated aide mémoire mimicry, are described.     

Why male butterflies are non-mimetic: natural selection,sexual selection,group selection,modification and sieving*

Thomas Belt suggested that the frequent limitation of mimicry in butterflies to the female resulted from sexual selection. Because female butterflies store sperm they can be fully fertile after only one mating; the reproductive success of a male is proportional to the number of times he mates. Sexual selection is therefore much stronger in males than females, with selection coefficients being greater by a small multiple of the number of times a female is courted during her life (long-lived species) or of the reciprocal of the female mortality rate between courtships (short-lived species). As butterflies of both sexes respond to colour when courting, sexual selection resists colour changes especially strongly in males. As a result, genes conferring new mimetic colour patterns can often become established in a butterfly population much more readily if their expression is initially limited to females; when the population size of a Batesian mimic, its model, and its predator fluctuates, such sex-limited genes have an enhanced probability of ultimate fixation in the population, and a reduced chance of loss; this effect is accentuated by the selection of modifiers which improve the mimicry. When the establishment of unimodal mimicry (expressed in both sexes) is favoured in a Batesian mimic, the gene tends to rise to an equilibrium frequency at which modifiers suppressing the expression of the mimicry only in males and'modifiers enhancing the mimicry only in females are favoured. The outcome is female-limited mimicry, or unimodal mimicry with better mimicry in the females, the males either retaining some of their sexual colour or the selective behaviour of the females becoming altered. In a Muellerian mimic there is no such equilibrium and selection ultimately favours expression of mimicry in both sexes and an appropriate alteration in the courtship responses. Hence Muellerian mimicry is seldom female-limited. Exceptional cases appear to result from the sexes flying in separate habitats. The genetical evidence in Papilio and Heliconius favours initial limitation of expression over subsequent modification as the usual basis for female-limited mimicry. Other explanations of female-limited mimicry can be found wanting in various ways; a higher predation rate on females could produce sex-limitation, but is probably not a strong factor. But the greater variability of the female in Lepidoptera may indicate lesser developmental stability, which could result in greater penetrance of mutants in the female, and hence account for the initial female-limitation. At very high densities of a mimetic species which has no non-mimetic form, mimicry tends to deteriorate more rapidly in a unimodal than in an otherwise identical sex-limited species. Although by itself this would equally favour male-limitation, and hence cannot explain the predominance of female-limitation, this effect may over evolutionary time be causing a slight increase in the proportion of sex-limited species among mimics. The stability of some mimetic polymorphisms is investigated by linear approximation: in some instances a stable equilibrium can be changed into an oscillating equilibrium by changes in the population size.     

Mimetic gain in batesian and Müllerian mimicry

Summary Starting from field investigations and experiments on mimetic butterfly populations a model for two mimetic species is developed. The model comprises various features such as the growth rates and carrying capacities of the two species, their unpalatability to predators, the recruitment and the training of the predators and, most important, the similarity of the two mimetic species. The model ranges from pure Batesian to pure Müllerian mimicry over a spectrum of possible cases. The mimetic gain is introduced as the relative increase in equilibrium density in a mimetic situation as compared to a situation where mimicry is not present. The dependence of this quantity on parameters as growth rate, carrying capacity, unpalatability, and similarity is investigated using numerical methods.     

Dorsal Forewing White Spots of Male <Emphasis Type="Italic">Papilio polytes</Emphasis>(Lepidoptera: Papilionidae) not Maintained by Female Mate Choice

Palatable animals sometimes mimic the color patterns of noxious animals to gain protection from predators. This phenomenon, known as Batesian mimicry, is seen in many butterflies of the genus Papilio, and in some species the mimicry is limited to females. Although female-limited Batesian mimicry has been hypothesized to be caused by females preferring to mate with non-mimetic males, this hypothesis is rarely tested. In this study, we tested whether female mate choice is driving female-limited Batesian mimicry in Papilio polytes. Males have white spots on the dorsal forewings, which are absent in mimetic female sand in the toxic model, Pachliopta aristolochiae. Hence, we conducted mate choice experiments to examine whether these white spots are important to females. We offered females a choice of males with intact dorsal forewing white spots and males with artificially blackened dorsal forewings, resembling the model. Females did not show a preference for males with the white spots, suggesting that they are not being maintained by female mate choice. Future studies should investigate the presence of female mate choice on other parts of males’ wings to further understand the role of female mate choice, as well as explore other factors driving female-limited mimicry in these butterflies.     

Independent evolution of sexual dimorphism and female‐limited mimicry in swallowtail butterflies (Papilio dardanus and Papilio phorcas)

Several species of swallowtail butterflies (genus Papilio) are Batesian mimics that express multiple mimetic female forms, while the males are monomorphic and nonmimetic. The evolution of such sex‐limited mimicry may involve sexual dimorphism arising first and mimicry subsequently. Such a stepwise scenario through a nonmimetic, sexually dimorphic stage has been proposed for two closely related sexually dimorphic species: Papilio phorcas, a nonmimetic species with two female forms, and Papilio dardanus, a female‐limited polymorphic mimetic species. Their close relationship indicates that female‐limited polymorphism could be a shared derived character of the two species. Here, we present a phylogenomic analysis of the dardanus group using 3964 nuclear loci and whole mitochondrial genomes, showing that they are not sister species and thus that the sexually dimorphic state has arisen independently in the two species. Nonhomology of the female polymorphism in both species is supported by population genetic analysis of engrailed, the presumed mimicry switch locus in P. dardanus. McDonald–Kreitman tests performed on SNPs in engrailed showed the signature of balancing selection in a polymorphic population of P. dardanus, but not in monomorphic populations, nor in the nonmimetic P. phorcas. Hence, the wing polymorphism does not balance polymorphisms in engrailed in P. phorcas. Equally, unlike in P. dardanus, none of the SNPs in P. phorcas engrailed were associated with either female morph. We conclude that sexual dimorphism due to female polymorphism evolved independently in both species from monomorphic, nonmimetic states. While sexual selection may drive male–female dimorphism in nonmimetic species, in mimetic Papilios, natural selection for protection from predators in females is an alternative route to sexual dimorphism.     

Model toxin level does not directly influence the evolution of mimicry in the salamander <Emphasis Type="Italic">Plethodon cinereus</Emphasis>

The resemblance between palatable mimics and unpalatable models in Batesian mimicry systems is tempered by many factors, including the toxicity of the model species. Model toxicity is thought to influence both the occurrence of mimicry and the evolution of mimetic phenotypes, such that mimicry is most likely to persist when models are particularly toxic. Additionally, model toxicity may influence the evolution of mimetic phenotype by allowing inaccurate mimicry to evolve through a mechanism termed ‘relaxed selection’. We tested these hypotheses in a salamander mimicry system between the model Notophthalmus viridescens and the mimic Plethodon cinereus, in which N. viridescens toxicity takes the form of tetrodotoxin. Surprisingly, though we discovered geographic variation in model toxin level, we found no support for the hypotheses that model toxicity directly influences either the occurrence of mimicry or the evolution of mimic phenotype. Instead, a link between N. viridescens size and toxicity may indirectly lead to relaxed selection in this mimicry system. Additionally, limitations of predator perception or variation in the rate of phenotypic evolution of models and mimics may account for the evolution of imperfect mimicry in this salamander species. Finally, variation in predator communities among localities or modern changes in environmental conditions may contribute to the patchy occurrence of mimicry in P. cinereus.     

Müllerian mimetic radiation of Delias butterflies (Lepidoptera: Pieridae) in Bali and Timor

Mimicry rings are present among Delias butterflies, and those butterflies are also considered to be mimetic models of other lepidopteran insects; however, experimental evidence for their unpalatability to predators is limited. In Bali and Timor, a total of three mimicry rings of Delias species are present; particularly, male and female D. lemoulti join different rings in Timor. The present study examined the unpalatability of Delias in Bali and Timor to the caged avian predator Pycnonotus aurigaster. The birds ate eight Delias species in similar numbers, and ate the palatable butterfly Mycalesis horsfieldii much more frequently than Delias butterflies. The result suggests that the three mimicry rings of Delias species in Bali and Timor are Müllerian rather than Batesian. Based on previous findings on their phylogenetic relationships, the Müllerian mimicry rings of Delias in Bali and Timor are suggested to have emerged through the convergent evolution and phylogenetic constraints of wing color patterns. In the D. hyparete species group, mimetic radiation may have occurred between Bali and Timor.     

Unpalatability of viceroy butterflies (Limenitis archippus) and their purported mimicry models,Florida queens (Danaus gilippus)

Summary Understanding the dynamics of defensive mimicry requires accurately characterizing the comparative palatability of putative models and mimics. The Florida viceroy butterfly (Limenitis archippus floridensis) is traditionally considered a palatable Batesian mimic of the purportedly distasteful Florida queen (Danaus gilippus berenice). I re-evaluated this established hypothesis by directly assessing palatability of viceroys and queens to red-winged blackbirds in a laboratory experiment. Representative Florida viceroys were surprisingly unpalatable to red-wings; only 40% of viceroy abdomens were entirely eaten (compared to 98% of control butterfly abdomens), and nearly one-third were immediately tasterejected after a single peck. In fact, the viceroys were significantly more unpalatable than representative Florida queens, of which 65% were eaten and 14% taste-rejected. Thus, viceroys and queens from the sampled populations exemplify Müllerian rather than Batesian mimicry, and the viceroy appears to be the stronger model. These findings prompt a reassessment of the ecological and evolutionary dynamics of this classic mimicry relationship.